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List:       openbsd-tech
Subject:    Re: ntpd: go into unsynced mode
From:       Otto Moerbeek <otto () drijf ! net>
Date:       2020-08-30 14:32:11
Message-ID: 20200830143211.GA95336 () clue ! drijf ! net
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On Sat, Aug 22, 2020 at 03:51:48PM +0200, Otto Moerbeek wrote:

> Hi,
> 
> At the moment ntpd never goes into unsynced mode if network
> connectivity is lost. The code to do that is only triggered when a
> pakcet is received, which does not happen. 
> 
> This diff fixes that by going into unsynced mode if no time data was
> processed for a while. 
> 
> An earlier version of this diff was tested by naddy@. Compared to that
> version, the needed period of inactivity is now three times as large
> and I set scale to 1, so recovery goes faster.
> 
> Please test and review,

anyone wants to ok?

	-Otto


> 
> Index: ntp.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/ntpd/ntp.c,v
> retrieving revision 1.165
> diff -u -p -r1.165 ntp.c
> --- ntp.c	22 Jun 2020 06:11:34 -0000	1.165
> +++ ntp.c	22 Aug 2020 13:48:34 -0000
> @@ -89,6 +89,7 @@ ntp_main(struct ntpd_conf *nconf, struct
>  	struct stat		 stb;
>  	struct ctl_conn		*cc;
>  	time_t			 nextaction, last_sensor_scan = 0, now;
> +	time_t			 last_action = 0, interval;
>  	void			*newp;
>  
>  	if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, PF_UNSPEC,
> @@ -402,6 +403,7 @@ ntp_main(struct ntpd_conf *nconf, struct
>  		for (; nfds > 0 && j < idx_clients; j++) {
>  			if (pfd[j].revents & (POLLIN|POLLERR)) {
>  				nfds--;
> +				last_action = now;
>  				if (client_dispatch(idx2peer[j - idx_peers],
>  				    conf->settime, conf->automatic) == -1) {
>  					log_warn("pipe write error (settime)");
> @@ -417,8 +419,24 @@ ntp_main(struct ntpd_conf *nconf, struct
>  		for (s = TAILQ_FIRST(&conf->ntp_sensors); s != NULL;
>  		    s = next_s) {
>  			next_s = TAILQ_NEXT(s, entry);
> -			if (s->next <= getmonotime())
> +			if (s->next <= now) {
> +				last_action = now;
>  				sensor_query(s);
> +			}
> +		}
> +
> +		/*
> +		 * Compute maximum of scale_interval(INTERVAL_QUERY_NORMAL),
> +		 * if we did not process a time message for three times that
> +		 * interval, stop advertising we're synced.
> +		 */
> +		interval = INTERVAL_QUERY_NORMAL * conf->scale;
> +		interval += MAXIMUM(5, interval / 10) - 1;
> +		if (conf->status.synced && last_action + 3 * interval < now) {
> +			log_info("clock is now unsynced");
> +			conf->status.synced = 0;
> +			conf->scale = 1;
> +			priv_dns(IMSG_UNSYNCED, NULL, 0);
>  		}
>  	}
>  
> 

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